METHOD AND APPARATUS FOR ELECTROMAGNETICALLY BRAKING MOTOR

PROBLEM TO BE SOLVED: To optimize performance of a brake assembly and to increase total efficiency. SOLUTION: An electromagnetic braking system and method is provided for selectively braking a motor using an electromagnetic brake having an electromagnet, a permanent magnet, a rotor assembly, and a brake pad. The brake assembly applies when the electromagnet is de-energized and releases when the electromagnet is energized. When applied, the permanent magnet moves the brake pad into frictional engagement with a housing, and when released, the electromagnet cancels the flux of the permanent magnet to allow a leaf spring to move the brake pad away from the housing. A controller has a DC/DC converter for converting a main bus voltage VMto a lower braking voltage based on certain parameters. The converter utilizes pulse-width modulation (PWM) to regulate the braking voltage. A calibrated gap is defined between the brake pad and permanent magnet when the brake assembly is released, and may be dynamically modified via the controller. COPYRIGHT: (C)2011,JPO&INPIT